Thursday, January 10, 2013

Living Thermometer

When I want to know how cold it is outside, I just have to look at the rhododendron leaves on the bush outside the office window. The colder it is, the tighter the leaves are curled! At about 25 degrees and below, they are drooping and tightly curled.

I often wondered why this strange thing happens so I looked it up. According to one web site....

The leaves curl because
they lose water, just as many other plants wilt. Severe droughts also cause
rhododendron leaves to droop and curl. The pores through which the plant
loses water and takes up air are located on the underside of the leaves.
When the leaves curl, these pores are protected, and the evaporation of
additional water is reduced. The curled leaves protect the rhododendron
plant from more water loss.

So on warm days, the leaves are open and perpendicular to the plant stem. As it gets closer to freezing, they start to droop. Below freezing, the leaves droop and curl. Pretty cool plant! I have my own thermometer just outside the window in winter!

1 comment:

LinkWithin

ShareThis

Please don't copy without asking!

The Appalachian Mountains are the oldest mountains in the world and an area of diverse natural beauty as well as home to unique people and places. In the 10 years we have lived here, we have made an effort to explore every nook and cranny of the area and we are still in the process. This is a nature lover's view to life in the Appalachian Mountains of North Carolina -- hiking, birds, wildlife, natural places to visit as well as eclectic healthy restaurants and unusual places to shop.